If I own a house in the clear and make a private transaction to trade my house for someone else's boat, I still own capital gains on the difference between what I bought the house for and what the boat is valued at. So if I bought the house for $250k and I wind up with a boat valued at $1M then I owe taxes on $750k in capital gains.

There's no "if it doesn't touch USD it doesn't trigger taxes" law because that would be instantly gamed and exploited.